* {
  margin: 0;
  position: 0;
}
body {
  width: 100%;
  height: 100%;
  background-color: skyblue;
}
.box {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  padding: 15px;
  width: 400px;
  height: 300px;
  background-color: #fff;
  box-shadow: 0 0 8px #eeeeee;
}
.box h1 {
  color: #1e9fff;
  font-size: 25px;
  text-align: center;
}
